The present invention relates to an improvement of a scroll machine for compressing fluid by means of a pair of associating scrolls.
U.S. Pat. No. 3,884,599 discloses an example of a conventional scroll machine which is shown in FIGS. 10 to 12 of this application. In FIGS. 10 to 12, a scroll machine includes a drive scroll 100 having a convolute scroll land 100a and a driven scroll 101 disposed in eccentricity with respect to the drive scroll 100 and having a convolute scroll land 101a associated with the land 100a of the drive scroll 100 to compress fluid. A coupling 102 is disposed between the drive scroll 100 and the driven scroll 101 and has a first groove 102a engageable slidably in an X direction with the drive scroll 100 and a second groove 102b engageable slidably in a Y direction with the driven scroll 101.
When the drive scroll 100 rotates, the driven scroll 101 is rotated through the coupling 102. That is, since the first groove 102a of the coupling 102 engages with the drive scroll 100 while the second groove 102b engages with the driven scroll 101, the coupling 102 transmits rotation of the drive scroll 100 to the driven scroll 101 while swinging in X and Y directions.
Thus, in the conventional scroll machine, fluid is compressed between the scrolls which are always in contact with the first and the second grooves of the coupling. Such continuous contact between the scrolls and the grooves of the coupling creates problems of heat generation and abrasion which lead a rapid degradation of sealing between the scroll lands and a vibration and noise problem due to the continuous swing motion of the coupling, resulting in a shortage of duration of the machine and a restriction of rotation speed of the machine.